I was given this Coleman Saluspa from a family member that used it for a while without issue. I went over the directions, set up as recommended, and it worked for several days without issue. I will say that I did use an underrated extension cord and the pump/ heating unit was in direct sun at the time (I didn't know any better at the time). One morning when I went out to the tub it was turned off. When I turned it back on by resetting the GFCI plug I got an "E04" code. I researched it and understood that the tub/ heating unit must have over heated due to direct sunlight. I let it cool, made sure the heating element was shaded but not covered directly. I also noticed the GFCI plug prong looked a little toasted (didn't notice prior to setting up) so I replaced the GFCI plug and got an appropriately gauged power cord. NOW the thermometer on the unit says the water is 99 degrees Fahrenheit yet the water is cool to the touch. The thermostat reading rises rapidly and when it exceeds 104 degrees I get another "E04" code. Where should I go from here?